Word: magma
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...scientists have a more modern theory. It is generally believed that the giant, continent-size plates forming the earth's outer shell crunch together in certain places, such as along the Ring of Fire. On plate slips under, heats up and begins to melt. This molten material, or magma, is lighter than neighboring and slowly rises, often triggering earth tremors. Eventually the magma may break through the surface as lava. In some cases, like that of Mount St. Helens, the magma remains in pools under the mountain, but still releases enough heat to cause explosive ejections of steam, fumes...
...extremely hard black grains, which laboratory examination revealed to be tiny diamonds. Institute Geochemist Emil Sobotovich explained that the little diamonds could only have been created under extraordinarily high pressures. Such conditions deep within the earth produce diamonds, which are brought to the surface in eruptions of molten magma through kimberlite, or volcanic, pipes. But extreme pressures also occur during high-velocity collisions between celestial objects; uralites, a class of meteorites that presumably have been involved in such deep-space impacts, contain such tiny diamonds. Since no volcanic pipes have been identified in the Tunguska area, Sobotovich concluded that...
Mount Usu had last erupted in 1945. Since then, magma, or semimolten rock from the mantle surrounding the earth's core, had been slowly and quietly rising through cracks under the peak of the mountain, building up tremendous pressures and triggering repeated earth tremors that rocked Hokkaido. Finally, on Aug. 7, the 725-meter (2,400-ft.) Usu awakened with a roar like that of a bomb. A huge black cloud soared to a height of 12,000 meters (39,000 ft.). A dense shower of gray ash and chunks of porous, rock-like pumice poured...
...separately printed booklet about Centennial, "is to create a universe." The reader is warned. "Three billion, six hundred million years ago," Michener begins, "the crust had formed, and the cooling earth lay exposed to the developing atmosphere." The next 110 pages are taken up with discourses on magma and glaciers, the planet's prehistoric upheavals. Then come the prehistoric beasts, which the author vaguely anthropomorphizes: a lovely Diplodocus wandering in the muck "toward dusk on a spring evening one hundred and thirty-six million years ago" finds herself growing "irritable...
Potentially the most promising geothermal sources lie in areas where molten rock, or "magma," is fairly close to the earth's surface. In theory, engineers can sink twin wells as deep as 20,000 feet to the hot underlying rock and then fracture it. Clean water, pumped down one hole, would be heated by the broken-up magma and would return up the other well as steam...